With the second Pillars of Eternity "expansion" White March: Part 2 concluding this chapter of the story it only makes sense to bundle it all together in to one package.
What does surprise me however is that according to an Amazon.de product listing that Gamebanshee discovered the Pillars of Eternity: GOTY is set to arrive only a couple of days after White March: Part 2, on February 19th.
This really is unusual since from a purely business perspective its best to first let the DLC sales dwindle down before introducing a bundle deal but if Obsidian and Paradox believe this to be the right move I certainly won't complain about getting all of it at a decent discount.
But even though the GOTY edition is most likely coming soon its still not a bad time to give Pillars of Eternity a try because its currently 50% off in the Steam sale. Not just that, the upcoming 3.0 update which will release alongside White March: Part 2 brings in new quests, an optional story-only mode, plenty of bug fixes, balance changes and much more.
So if you're a fan of oldschool combat RPGs I recommend you give Pillars of Eternity a try because it really is the best out of the currently available ones. As a parting note here's a video showcasing all of the features coming in with update 3.0: